反应详情

温度

85 °C

The 4-((5,5-dimethyl-1,3-dioxan-2-yl)methoxy)-2,3-dimethylpyridine1-oxide (3.1 g, 11.6 mmol) obtained by the step (1c) was mixed with acetic anhydride (9.87 ml, 104 mmol). After the mixture was stirred at 85° C. for 45 minutes, acetic anhydride was removed. The residue was dissolved in methanol (40 ml) and a 5N aqueous sodium hydroxide solution (5.1 ml, 25.5 mmol) was added to the mixture while cooling on ice. The mixture was stirred at room temperature for one hour. Methanol was distilled off and ice water was added to the residue, which was then extracted with ethyl acetate. The organic layer was washed with a saturated saline solution, dried over anhydrous magnesium sulfate. After the solvent was distilled off, the resultant mixture was purified by silica gel column chromatography (silica gel: 120 g, elution solvent: ethyl acetate/heptane=1/4 to 4/1) to obtain the title compound (1.23 g, yield: 39.7%) as a light yellow oil.

1. customacetic anhydride was removed
2. dissolutionThe residue was dissolved in methanol (40 ml)
3. temperaturewhile cooling on ice
4. stirringThe mixture was stirred at room temperature for one hour
5. distillationMethanol was distilled off
6. additionice water was added to the residue, which
7. extractionwas then extracted with ethyl acetate
8. washThe organic layer was washed with a saturated saline solution
9. dry with materialdried over anhydrous magnesium sulfate
10. distillationAfter the solvent was distilled off
11. customthe resultant mixture was purified by silica gel column chromatography (silica gel: 120 g, elution solvent: ethyl acetate/heptane=1/4 to 4/1)